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Q & A: Can two gamma ray beams produce e+ e- pairs?

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Most recent answer: 09/05/2013
Q:
I have been reading about antimatter. I have read about the annihilation of antimatter when it comes into contact with matter. My understanding is that this process creates gamma rays and in some instances nuetrinos. My question is whether we have been able to reverse this process and make antimatter and matter from gamma rays alone, without the interaction of other particles? Thank you
- Lawrence (age 17)
St. Louis, MO
A:

In principle yes, in practice it's difficult.   The laws of particle-antiparticle annihilation and production work both directions.  What you need is a pair of highly intense gamma ray sources with energies well above the rest energy of an electron, 511 KiloVolts each in order to achieve this.  I'm not aware of this being done yet.  Maybe some astute reader can point me to a reference.   Many examples of particle-antiparticle production have been seen at LEP, SLAC and other electron colliders that do the same thing only with the the 'virtual photons' that are associated with the electrons.  

 

LeeH

 


(published on 09/05/2013)

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